Portable radio transceivers typically include a one-quarter wavelength end-fed, helical, or one-half wavelength center-fed dipole antenna that protrudes from the radio housing. The antenna is usually flexible in design to prevent damage, not only to the antenna itself, but also to any person who may come into contact with the antenna. A connector typically attached the antenna to the radio housing so that the antenna can be easily removed from the radio.
There are several drawbacks to these prior art antenna designs. First, because the antenna protrudes from the housing, it extends the overall length of the radio, making the radio more cumbersome. The flexible design and connector make the antenna expensive to manufacture, and repeated flexing of the antenna over an extended period of time can result in breakage. These prior art antennas also typically require some type of impedance matching network between the final R.F. power amplifier and the antenna.
Accordingly, it would be desirable if an antenna could be developed which has a very low profile such that it could be mounted in or on the radio housing without protrusion. It would also be desirable to eliminate the impedance matching network and reduce the manufacturing cost of the antenna. It would be advantageous, however, to approximate the radiation pattern of the prior art center-fed dipole antenna.